Connecting units of the above type are known which substantially comprise an axially symmetrical stator having a number of radial contact blades; and a movable member supported coaxially by the stator, rotated by helicopter tail rotor actuating means, and having annular conducting tracks which cooperate in sliding manner with the contact blades to connect the stator and movable member electrically.
More specifically, the stator is normally fixed rigidly to an outer casing of a power transmission unit interposed between the tail rotor hub and a drive unit of the helicopter.
The movable member, on the other hand, is supported radially by the stator by means of a number of bearings, and is rotated by a shaft of the tail rotor transmission unit.
A major drawback of connecting units of the above type lies in operating wear producing slack between the contacting components of the bearings supporting the movable member, thus altering the relative positions of the stator and movable member, and resulting in precarious, or even no, electric connection between the conducting tracks and sliding contacts.